Typewriter bail structure



Sept. 22, 1959 L. E. PALMER TYPEWRITEIR BAIL STRUCTURE Original Filed Oct. 21, 1953 INVENTOR. LEON E. PALMER TYPEWRITER BAIL STRUCTURE Leon E. Palmer, Lexington, Ky., assignor to International Business Machines Corporation, New York, N.Y., a corporation of New York Original application October 21, 1953, Serial No. 387,416, How Patent No. 2,862,594, dated December 2, 1958. and this application April 16, 1958, Serial No.

Claims. (Cl. 197-138) This invention relates to typewriters, and more particularly to bail structures for holding paper in engagement with the platen of a typewriter. The present application is a division of applicants copending application Serial No. 387,416 filed October 21, 1953, now Patent Number 2,862,594.

It is customary to provide on a typewriter a bail having pressure rolls which cooperate with the platen to hold paper which passes around the lower and front portion of the latter, with yielding pressure against the upper surface of the platen. This bail should be so constructed and supported that it may be moved manually forward to a position where paper may be inserted or adjusted on the platen without interference. It should also be so mounted that it may be swung upwardly out of the way to permit erasures to be made easily by the operator. When the bail is swung downwardly while extended, it may easily be brought into engagement with the front surface of the paper, and then movement of the bail rearwardly in the proper manner will cause the paper to be engaged with the platen without creasing. It is desirable that the bail structure be movable by the operator to any one of its positions and be yieldably held in each of the positions to which it is moved.

An object of the invention is to provide an improved paper bail for a typewriter.

Another object is to provide an improved paper bail wherein the bail always tends to smooth a work sheet onto the platen of a typewriter carriage.

Still another object is to provide a paper bail which is engageable with the top front surface of a platen and may either be moved horizontally forward from the platen or be swung upwardly to a raised position, with means acting on the bail to yieldably hold it in any one of the positions to which it is moved.

Yet another object is to provide an improved paper bail which is normally movable from a raised position to a substantially horizontal position in which pressure roll- ,ers on the bail are spaced forwardly of a platen, the bail being movable from such horizontal position rearwardly to engage the paper with the top front surface of the platen.

Other objects of the invention will be pointed out in the following description and claims and illustrated in the accompanying drawings, which disclose, by way of example, the principle of the invention and the best mode, which has been contemplated, of applying that principle.

In the drawings:

Fig. 1 is a perspective view showing a portion of a typewriter with the improved bail structure in its raised position.

Fig. 2 is a side elevational view showing the bail structure in other positions.

As shown in the drawings, the paper bail, generally designated 1, is fixed to a rod 2 which is rotatably supported at its ends by side plates 3, one of which is shown in Fig. 1, on the typewriter. The bail has, at each end,

1&6

a hinge arm 4 brazed on the rod 2 adjacent the side plate 3, and an extension arm 5 pivotally connected at 6 to the outer end of the hinge arm. Extending between the other ends of the arms 5 is a bail rod 8 carrying rollers 9 at spaced points along its length, the rollers being engageable with a platen 10 for holding paper against the upper front surface of the platen. Each of the extension arms is provided with a bent-over ear portion 12 which is engageable with the rear edge of the hinge arm for limiting the swinging of the extension arm relative to the hinge arm in a clockwise direction. Extending between the sides of the typewriter is a rod 14 which is engageable by the extension arms 5 to limit the upward swinging of the bail to the position shown in Fig. 1. When the bail arms 5 are moved to a horizontal position with the rollers 9 engaging the platen, the ear portions 12 on the arms 4 engage the rod 14- for holding the bail in its proper position.

Each of the bail arms 5 has a portion 15 extending beyond the pivotal connection 6 to the arm 4, and provided on the portion 15 is a bearing portion 16 having sliding engagement with a spring arm 18 pivotally supported by a stud 19 extending from the side plate 3. Arranged on the stud is a spring 26 acting on a tail portion of the spring arm for urging the latter in a clockwise direction against the bearing portion 16.

The spring arms are each provided with surfaces 22 and 23 sloping downwardly at opposite sides of an elbow 24 and engageable with the bearing portion 16. When the bail is in a position with the rollers 9 engaging the platen, as shown in Fig. 2, the bearing portion 16 engages the surface 23 on the spring arm 18. The force on the bearing portion by the spring arm is such as to urge the extension arm 5 about the pivot 6 in a direction to hold the rollers 9 against the platen and, at the same time, to urge tne hinge arm 4 in a clockwise direction to hold the ear portion 12 against the rod 14. When the bail is moved horizontally forward to the position shown in broken lines in Fig. 2, the bearing portion 16 moves over the elbow 24 and engages the surface 22 on the spring arm. It will be seen that the action of the spring arm on the bearing is such that the extension arm 5 is still urged in a counter-clockwise direction and, at the same time, the force applied through the extension arm and the pivot connection 6 to the arm 5 is such as to hold the latter in its forward rocked position. The result is that the bail is yieldably held in its forward horizontal position.

When the bail is swung to its raised position as shown in Fig. 1, the bearing 16 engages the spring arm 18 at a point located slightly to the right of the elbow 24. The action of the spring arm at this time is such as to urge the arm portion 5 about the pivot 6 in a clockwise direction, and also to urge the hinge arm 4 in a clockwise direction about the rod 2. The movement of the arm 5 relative to the arm 4 is limited by engagement of the bent portion 12 with the rear edge of the arm 4, and the movement of the bail in a clockwise direction is limited by engagement of the bail arm 5 with the rod .14. It will be appreciated that the spring arm 18 operates in each position of the bail to hold both arms 4 and 5 yieldingly in their set positions.

Fixed to each of the side plates 3 adjacent the platen and overlying the latter is a guide cam 26 which is engageable by a roller 27 mounted on the extension arm 5 between its outer end and the pivot 6. When the bail is in its horizontal extended position as shown in Fig. 2, the rollers 27 engage the guide cams 26 and hold the bail arms 5 free of the platen. The guide cams are inclined slightly from their forward edges toward the rear so that movement of the bail rearwardly from its extended position causes the bail rollers 9 to lift the paper and move it into engagement with the platen without any bulging or wrinkling at points in front of the platen. Just before the bail reaches the-full line position shown in Fig. 2, the rollers 9 engage the paper with the platen. As the bail moves from this point to the full line position, the rollers 9 roll the paper over the platen surface while the rollers 27 move out of engagement with the guide cams 26 which slope downwardly at their rear ends.

If the bail is moved by the operator horizontally forward only part way to its extended position in order to make some adjustment to the paper, then the bail will be moved rearwardly again by the spring arm as soon as the operator releases it. When the bail is moved, however, to its full extended position, the spring arm operates to hold it in such position.

While there have been shown and described and pointed out the fundamental novel features of the invention as applied to a preferred embodiment, it will be understood that various omissions and substitutions and changes in the form and details of the device illustrated and in its operation may be made by those skilled in the art without departing from the spirit of the invention.

What is claimed is:

1. In a platen supporting carriage for typewriters and similar office machines, an improved paper bail comprising a pair of hinge arms pivotally supported on said carriage, a pair of extension arms mounted respectively on a pivot point carried by each of said hinge arms, a cross bail interconnecting said extension arms at one side of said pivot point, a pair of extension arm bearings mounted respectively on each of said extension arms at the other side of said pivot point, a pair of spring arms mounted on said carriage and having surfaces slidably engaging said extension arm bearings to hold said cross bail in or out of engagement With said platen depending upon whether the points of contact between said surfaces and said extension arm bearings are rearwardly or forwardly respectively of said pivot point.

2. In a platen supporting carriage for typewriters and similar oflice machines, an improved paper bail comprising hinge arms pivotally supported on said carriage, extension arms, a pivot for mounting said extension arms on said hinge arms, a cross bail positioned parallel to the platen axis and interconnecting the ends of said extension arms at one side of said pivot, extension arm bearings mounted on said extension arms at the other side of said pivot, spring arms supported on said carriage and biased into engagement with said extension arm bearings to urge said extension arms about said pivot thereby to hold said paper bail respectively in or out of engagement with said platen depending upon whether said extension arm bearings are behind or in front of said pivot point, a pair of guide bearings mounted on the cross bail side of said extension arms, and cam surfaces mounted on said carriage to cooperate with said guide bearings for guiding said cross bail into engagement with said platen.

3. A bail structure cooperating with a platen on a typewriter carriage comprising, in combination, a pair of binge arms pivotally connected to said carriage adjacent its ends, a pair of extension arms pivotally connected to the outer ends of said hinge arms, a bail rod supported by the outer ends of said extension arms in a position extending parallel to said platen, rollers mounted on said bail rod and engageable with said platen, bearing members supported by said extension arms, spring arm): pivotally connected to said carriage and yieldably engaging said bearing members, and surfaces on each of said spring arms opopsitely inclined from a point between its ends, one of said surfaces acting on said bearing members for yieldingly holding said hinge arms and said extension arms in positions to engage said rollers with said platen, the other of said,v surfaces acting on said bearing members upon movement of said rollers forwardly of the platen and operating to yieldingly hold said hinge arms and said extension arms in positions to maintain said rollers in their forward positions.

4. A bail structure cooperating with a platen on a typewriter carriage comprising, in combination, a pair of hinge arms pivotally connected to said carriage adjacent its ends, a pair of extension arms pivotally connected to the outer ends of said hinge arms, a bail rod supported by the outer ends of said extension arms in a position parallel to said platen, rollers on said bail rod, said rollers engaging said platen when said extension arms are horizontal and said hinge arms are substantially in vertical positions, said we tension arms being adapted either to swing upwardly from this position or to move horizontally forward While said hinge arms pivot forwardly, bearing members on said extension arms, and spring arms acting on said bearing members and operating to hold said hinge arms and said extension arms in any one of the positions to which they are moved.

5. The structure of claim 4 in which said spring arms have surfaces inclined in opposite directions to form elbows, one of said surfaces on each spring arm acting on said bearing members for urging said hinge arms away from said platen when moved to a vertical position and, at the same time, urging said extension arms toward or away from said platen depending on whether said extension arms are in horizontal or raised positions, and the other of said surfaces acting on said bearing members when said extension arms are in horizontal extended positions for urging both said hinge arms and said extension arms toward said platen.

References Cited in the tile of this patent UNITED STATES PATENTS 1,508,836 Degener Sept. 16, 1924 2,327,423 Helmond Aug. 24, 1943 2,555,645 Helmond June 5, 1951 2,566,930 Crumrine Sept. 4, 1951 2,746,590 Lemos May 22, 1956 

